1. Technical Field
The invention is concerned with the fabrication of silica-based optical fiber drawn from preforms which include sol-gel-produced glass. Early use is expected to take the form of low-loss single-mode fiber prepared from composite preforms constituted of sol-gel-produced overcladding tubes enclosing core rods prepared by usual fiber fabrication processes.
2. Description of the Prior Art
Co-pending U.S. patent application, Ser. No. 07/930,125, filed Aug. 14, 1992, represents the breakthrough to finally realize the economy implicit in use of sol-gel prepared silica-based glass bodies. In one use, tubular bodies, together with cores prepared by soot processing or by Modified Chemical Vapor Deposition, make up the composite preforms from which optical fiber may be drawn. That patent application describes incorporation of an organic polymer in the sol to avoid cracking of the gelled body during drying. Subsequent polymer removal during firing results in final drawn fiber of quality commensurate with that produced by more expensive methods now in use.